This two-year study proposes to analyze the parity progression from zero through the second child among female marriage cohorts formed after 1964. It uses data from the 1975 and 1980 June Current Population Surveys and tests hypotheses in four areas: 1) trends and differentials in the tempo of childbearing; 2) relative effects of social, economic and demographic variables on the parity progression; 3) racial and ethnic differences in current family formation and; 4) secular versus generational effects in family formation. Recent shifts in childbearing suggest both persistence and change in the determinants of family formation visible over this five-year interval. The study hypothesizes that current levels of delayed initiation of childbearing and thus voluntary childlessness are short-term phenomena with heavy secular influences; that fertility preferences are generally high among both Hispanic and black women but that the family formation of blacks will involve more spacing; and that family formation has been modified by both secular and generational influences, where the former (especially as they concern economic need and the status of women) are primarily responsible for the uncertainty now observed over if and when to commence childbearing. Although this research is aimed primarily at key demographic issues, it has a "hidden agenda" of a practical nature--the problems under study are precisely the ones which will permit early prediction of the eventual reproduction behavior of young women and thus give "early warning" of future trends of fluctuations in fertility and of the factors that cause them.